1. Field of the Invention
The present invention relates to glass fiber chemical delivery systems, more particularly, to a glass particulate coated intravascular stent.
2. Prior Art
In patients suffering from certain cardiovascular diseases which cause formation of atherosclerotic plaques within blood vessels, balloon angioplasty has been somewhat successful in reopening blood vessels blocked by such plaques. In order to prevent the blood vessels from recollapsing following balloon angioplasty, it is common for a stent to be inserted into the blood vessel to act as a brace against the inner wall of the blood vessel. Typically, the stent is an expandable stainless steel mesh in which a balloon is disposed. The stent and balloon assembly is inserted into the blood vessel of the patient with a catheter. The balloon is inflated causing the stent to assume a substantially cylindrical shape and engage the walls of the blood vessel. The catheter and balloon are then withdrawn from the blood vessel and the stent remains in position to maintain the blood vessel in an open state. However, it has been found that nearly 70% of patients having intravascular stents experience restinosis in the location of the stent. The stent itself apparently is an irritant to the cells of the blood vessel wall thus stimulating plaque to reform to an even greater degree than the original blockage caused by the first treated plaque.
One solution to this problem of restinosis is to deliver a drug to the blood vessel wall which inhibits or prevents the cells of the blood vessel wall from producing plaque. In particular, certain genes have been identified which will transfect the cells of the blood vessel wall and prevent the cells from producing plaque. Such gene therapy is gaining acceptance in the treatment of cardiovascular disease; however, the delivery of a gene to a specific location within a blood vessel wall remains problematic. Moreover, such a gene or other drug delivered to the location of an intravascular stent should provide sustained relief from the formation of plaque.
Accordingly, a need remains for an intravascular stent which inhibits or prevents restinosis and for a sustained release chemical delivery system which is compatible with a biological environment or other environments.